If you consider that A Tale of Two Wastelands -- where people forward-ported the Fallout 3 world to the Fallout: New Vegas engine and ruleset -- was successful, that could be pretty solid. I still think I'd forward-port Fallout: New Vegas to the current Bethesda engine before I'd forward-port Fallout 3, though. Fallout: New Vegas was a better game.
Tale of Two Wastelands is a total conversion mod for Fallout: New Vegas that merges the entire content of Fallout 3 and its DLC and New Vegas into one game. The mod implements features introduced in New Vegas into Fallout 3, such as the Companion Wheel, crafting recipes, and weapon mods. Players can freely traverse between the two games on a single save file, keeping all of their items and their progression between game worlds.[76][77][78][79]
Also, most Fallout: New Vegas mods worked with Tale of Two Wastelands, which was pretty cool.